5.3 MPG 1984 28' Fleetwood Jamboree

[RVwantabe]

Does anyone know if this millage sounds right or do I need to get this engine tuned up? It's a 1984 E350 chasis with a 460 engine. I took it out to Ohio through west virginia and into PA to support my brother inlaw with a charity walk across America he started in Sanfansico in Jun and is now comming through PA to end in Ocean City NJ. I put on over 1000 miles to get there and spend two weeks to help support his walk and bought this RV to use as a support vehicle. First RV Trip ever everything worked great and loved the RV but was disapointed in the MPG speed 60 and under tire pressure 55PSI 50000 miles on truck. Let me know if there is anything I can do to improve it as when he get closer to philadelphia I going to take it out again for a week to help get him to NJ. Thanks

P.S. Check out his site (Mikeywalks.com) and show your support.

[LVJ58]

Does sound a bit low, are you towing anything with your class C? Check the max pressure allowable in your tires, should show on the sidewall. If possible you might want to increase pressure 5 or more psi to reduce rolling friction of tires.

Not sure what carburetor it uses, but you may want to have it checked out, might need a rebuild. Also have the distributor timing checked for proper setting. At 60mph I would think you should be getting around 7+ mpg.

Good luck and safe travels...

[450Donn]

The Ford 460 was never noted for being fuel efficient, however that seems bad even for that motor. Get a tune up, change the oil and filter, have the transmission serviced. Air the tires up some more might help you a little. While your at it, have the distributor rebuilt and check on timing chain wear. As I remember that motor was pretty hard on timing chains and they needed to be replaced at around 50K miles.

[southland]

460 engines are not known for great mileage. Had one, first and last, that I did lots of mods on and could never get over 6.5mpg. Did get a little more power but no fuel increase. 55psi on the tires sound a little low but not sure on that. If pressure is low, will effect your mileage.

[southland]

Quote:

Originally Posted by 450Donn The Ford 460 was never noted for being fuel efficient, however that seems bad even for that motor. Get a tune up, change the oil and filter, have the transmission serviced. Air the tires up some more might help you a little. While your at it, have the distributor rebuilt and check on timing chain wear. As I remember that motor was pretty hard on timing chains and they needed to be replaced at around 50K miles.

Sounds like we are on the same page, you posted as I was writing reply.

[stuhly]

Had a 85 Georgie Boy with a 454. Got 5.5 mpg uphill, downhill, headwind, tailwind, loaded or empty. I suspect the 460 in those years are close to the dame

[frankdamp]

We had an '85 Jamboree "Spirit" 26' Class C, a rig they only made for one model year. It had the carb-equipped Ford 460. At sea level we got just over 6 mpg and at altitude it dropped to a little over 4.

Check for problems related to very high under-hood temps. We found the brake fluid had lost all its volatile components and looked like molasses in Anchorage in January. The goop had travelled into the rear drum brakes and the pull-off springs couldn't release the brakes.

A friend who worked at Ford said that the 460, if being run at full throttle up hill at relatively low ground speed, could get the exhaust manifolds glowing dull red, about 1400 degrees F.

Class C rigs of that vintage need a lot of extra cooling air going through the engine compartment, blowing over the manifolds. I couldn't figure out, in our first season with that POS, why the interior surface of the doghouse got hot enough to melt the soles of our shoes.

We put a couple of fans to increase airflow under the hood and also put a couple of extra layers of insulation on the engine-side of the doghouse. We finally wised up and sold that junk pile. With what we lost on the original purchase price, and the cost of all the fix-ups that I couldn't tqckle myself, we figured that each night's camping over two seasons had cost about $400!

We sold it on consignment through a local dealer, assuming that whoever bought it wouldn't come looking for us. They never did!

I'd suggest an engine swap, if you can afford it, to the last EFI 460's that were sold before the V-10 came out. Ford had got the 460 to about as good as it could be by then. Put tubular headers on it, to minimise the under-hood heating effects and add some fans for airflow over the manifolds.

[Conquest102]

Check the air filter and PVC filter and PVC valve. They will cause a rich mix which just wastes gas. You should also consider pulling each plug to inspect for rich or lean fuel the wires while your at it as well for cracks or burns from the engine. You should get around 6-8 if your not overloaded. That would KILL the mileage as fast as any of the other things as well. I would also bet by the year the engine is CARBED so YES a GOOD carb rebuild might be in your future.

[RobRV]

Tuned Properly and Driven at 55 MPH not 60+ will get You 7-7.5 MPG on that 460! Go Faster and the Mileage just plain Sucks!

[George Schweikle]

What is your driving style?. If you drive your RV like a car (stomping the gas, accelerating hard from traffic lights, keeping up with fast traffic, etc) the result will be as you describe. As hard as it is, driving "with an egg on the gas pedal", will improve the mileage. If you're already doing this, then please ignore my post...

Quote:

Originally Posted by RVwantabe Does anyone know if this millage sounds right or do I need to get this engine tuned up? It's a 1984 E350 chasis with a 460 engine. I took it out to Ohio through west virginia and into PA to support my brother inlaw with a charity walk across America he started in Sanfansico in Jun and is now comming through PA to end in Ocean City NJ. I put on over 1000 miles to get there and spend two weeks to help support his walk and bought this RV to use as a support vehicle. First RV Trip ever everything worked great and loved the RV but was disapointed in the MPG speed 60 and under tire pressure 55PSI 50000 miles on truck. Let me know if there is anything I can do to improve it as when he get closer to philadelphia I going to take it out again for a week to help get him to NJ. Thanks P.S. Check out his site (Mikeywalks.com) and show your support.

[ga traveler]

Most of the chevys in this time frame had a problem with the carb. float absorbing gas and riding too low in the bowl. This causes the carb. to run very rich and get loww gas millage. I would try a new float.

[jlyon69]

I had a 1992 Four Winds 29ft with a fuel injected 460. I pulled a 16ft enclosed trailer with 2 full dressed Harleys, tools and other stuff. Weight was about 5,000 lbs. We made many trips from Michigan to Florida and would average 7.5 MPH. With tail winds (my favorite ) I got as high as 8.5 MPH. One time on our way to S.D. we hit some major head winds and only got 5.8.

I generally tried to manage 65 MPH+, but probably averaged 60-62. I always made sure my air filter was clean and the tires fully inflated. If memory serves, the max was 70psi and I would never let them get below 65psi.

[rough road]

Ah, our old 460 don't miss it one bit but we did save alot on propane; did most of our baking on top of the doghouse. We did two exhaust manifolds, wonder why?

Our first bulk tank truck was a gmc with a big block 454, with 20 ton or so of liquid freight that chev got the same mileage as the Ford in our Shasta....

[awarnes]

I think you may be stuck with mileage at that range. I have an 87 Allegro with a 454 and have had a tune up and everything else done with the exception of the carb. get 5.5. I drive very conservative and got about the same mileage as before the tune up. I reviewing this with my mechanic he said I should be getting around 7 to 8, but I may only keep the rig for this year and then trade up. Don't know if I want to put a few hundred bucks into a carb for the under 1000 miles or so I will travel this summer. Given the age of yours and depending on how much travel you will do, how long you will keep it. After the tune up do you want to drop $$$$ to get a couple more miles per gallon?

Arnold